distribution/docs/auth/basic/htpasswd.go

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package basic
import (
"crypto/sha1"
"encoding/base64"
"encoding/csv"
"errors"
"os"
"regexp"
"strings"
"golang.org/x/crypto/bcrypt"
)
// AuthenticationFailureErr - a generic error message for authentication failure to be presented to agent.
var AuthenticationFailureErr = errors.New("Bad username or password")
// HTPasswd - holds a path to a system .htpasswd file and the machinery to parse it.
type HTPasswd struct {
path string
reader *csv.Reader
}
// AuthType represents a particular hash function used in the htpasswd file.
type AuthType int
const (
PlainText AuthType = iota
SHA1
ApacheMD5
BCrypt
Crypt
)
// String returns a text representation of the AuthType
func (at AuthType) String() string {
switch(at) {
case PlainText: return "plaintext"
case SHA1: return "sha1"
case ApacheMD5: return "md5"
case BCrypt: return "bcrypt"
case Crypt: return "system crypt"
}
return "unknown"
}
// NewHTPasswd - Create a new HTPasswd with the given path to .htpasswd file.
func NewHTPasswd(htpath string) *HTPasswd {
return &HTPasswd{path: htpath}
}
var bcryptPrefixRegexp *regexp.Regexp = regexp.MustCompile(`^\$2[ab]?y\$`)
// GetAuthCredentialType - Inspect an htpasswd file credential and guess the encryption algorithm used.
func GetAuthCredentialType(cred string) AuthType {
if strings.HasPrefix(cred, "{SHA}") {
return SHA1
}
if strings.HasPrefix(cred, "$apr1$") {
return ApacheMD5
}
if bcryptPrefixRegexp.MatchString(cred) {
return BCrypt
}
// There's just not a great way to distinguish between these next two...
if len(cred) == 13 {
return Crypt
}
return PlainText
}
// AuthenticateUser - Check a given user:password credential against the receiving HTPasswd's file.
func (htpasswd *HTPasswd) AuthenticateUser(user string, pwd string) (bool, error) {
// Open the file.
in, err := os.Open(htpasswd.path)
if err != nil {
return false, err
}
// Parse the contents of the standard .htpasswd until we hit the end or find a match.
reader := csv.NewReader(in)
reader.Comma = ':'
reader.Comment = '#'
reader.TrimLeadingSpace = true
for entry, readerr := reader.Read(); entry != nil || readerr != nil; entry, readerr = reader.Read() {
if readerr != nil {
return false, readerr
}
if len(entry) == 0 {
continue
}
if entry[0] == user {
credential := entry[1]
credType := GetAuthCredentialType(credential)
switch(credType) {
case SHA1: {
sha := sha1.New()
sha.Write([]byte(pwd))
hash := base64.StdEncoding.EncodeToString(sha.Sum(nil))
return entry[1][5:] == hash, nil
}
case ApacheMD5: {
return false, errors.New(ApacheMD5.String()+" htpasswd hash function not yet supported")
}
case BCrypt: {
err := bcrypt.CompareHashAndPassword([]byte(credential),[]byte(pwd))
if err != nil {
return false, err
}
return true, nil
}
case Crypt: {
return false, errors.New(Crypt.String()+" htpasswd hash function not yet supported")
}
case PlainText: {
if pwd == credential {
return true, nil
}
return false, AuthenticationFailureErr
}
}
}
}
return false, AuthenticationFailureErr
}